The purpose of this application is to request funding for a comprehensive research program on the social behavior, biology and spontaneous diseases of nonhuman primates maintained at the Caribbean Primate Research Center (CPRC). This objective will be accomplished through support of the animal resources at Cayo Santiago (CS) and Sabana Seca (SS), the CPRC Skeletal Collection, and preliminary investigations to be conducted by CPRC staff and collaborating scientists from the United States and Canada. Funding is requested to augment the commitment made by the University of Puerto Rico to support the CPRC when the previous NIH core grant (RR-01293) terminated on 30 June 1985. While additional long-term funding has been requested from the legislature of the Commonwealth of Puerto Rico to lend stability to the CPRC and to rebuild its facilities to meet AAALAC Accreditation standards, NIH support is required for the animal resources and research if the CPRC is to achieve its full potential. The CPRC offers investigators in the international scientific community a number of attractive features which justify NIH support as requested in this application: (1) The free-ranging rhesus monkey colony on CS. Computerized data (identity, age, sex, maternity, social group and reproductive history) on nearly 4,000 monkeys dating back to 1956 (six generations) are more detailed and in-depth than for any other nonhuman primate population in the world. This unique data base provides the background information required to test complex behavioral hypotheses and to study associations between spontaneous diseases in the population with age, sex, reproductive history and heredity; (2) CS-derived macaques maintained at SS that are available for more intensive research than is feasible on CS, six New and Old World monkey species including a breeding colony of patas monkeys, a free-ranging population of hybridizing Bolivian and Guyanan squirrel monkeys, and a number of aged rhesus monkeys; (3) The CPRC Skeletal Collection located at the Medical Sciences Campus which contains nearly 1,000 skeletons of seven monkey species, including over 600 from CS macaques of known staff capable of supporting a wide variety of behavioral and biomedical research at relatively low cost; (5) Secure animal facilities; and, (6) Computer access, office space and on-site housing for visiting scientists and students at both CS and SS.